U.S. patent application number 15/547966 was filed with the patent office on 2018-01-25 for rotating electric machine, elevator hoist, and method for magnetizing and demagnetizing permanent magnet of rotating electric machine.
This patent application is currently assigned to Mitsubishi Electric Corporation. The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Akira HASHIMOTO, Sachiko KAWASAKI, Hironori TSUIKI, Takashi UMEDA.
Application Number | 20180026502 15/547966 |
Document ID | / |
Family ID | 56615598 |
Filed Date | 2018-01-25 |
United States Patent
Application |
20180026502 |
Kind Code |
A1 |
KAWASAKI; Sachiko ; et
al. |
January 25, 2018 |
ROTATING ELECTRIC MACHINE, ELEVATOR HOIST, AND METHOD FOR
MAGNETIZING AND DEMAGNETIZING PERMANENT MAGNET OF ROTATING ELECTRIC
MACHINE
Abstract
A rotating electric machine includes: a stator having an
armature core having slots formed between magnetic pole teeth, and
a plurality of coils each of which is wound so as to straddle a
plurality of the magnetic pole teeth; and a rotor including a
plurality of permanent magnets disposed at certain intervals on an
outer peripheral surface of the magnetic yoke, and the coils
include an armature coil for driving the rotating electric machine
and a non-armature coil for magnetizing or demagnetizing the
permanent magnets of the rotor.
Inventors: |
KAWASAKI; Sachiko; (Tokyo,
JP) ; TSUIKI; Hironori; (Tokyo, JP) ;
HASHIMOTO; Akira; (Chiyoda-ku, Tokyo, JP) ; UMEDA;
Takashi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Chiyoda-ku, Tokyo |
|
JP |
|
|
Assignee: |
Mitsubishi Electric
Corporation
Chiyoda-ku, Tokyo
JP
|
Family ID: |
56615598 |
Appl. No.: |
15/547966 |
Filed: |
January 18, 2016 |
PCT Filed: |
January 18, 2016 |
PCT NO: |
PCT/JP2016/051288 |
371 Date: |
August 1, 2017 |
Current U.S.
Class: |
310/179 |
Current CPC
Class: |
H02K 3/493 20130101;
H02K 11/225 20160101; H02K 3/28 20130101; H02K 21/14 20130101; H02K
1/16 20130101; B66B 11/043 20130101; H02K 21/145 20130101; H02K
15/03 20130101; H02K 5/1732 20130101 |
International
Class: |
H02K 15/03 20060101
H02K015/03; B66B 11/04 20060101 B66B011/04; H02K 3/28 20060101
H02K003/28; H02K 21/14 20060101 H02K021/14; H02K 5/173 20060101
H02K005/173 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2015 |
JP |
2015-023803 |
Claims
1. A rotating electric machine comprising: a stator including an
armature core including a back yoke having an annular shape, a
plurality of magnetic pole teeth extending radially inward from the
back yoke, and slots surrounded by the back yoke and the magnetic
pole teeth, and a plurality of coils each of which is wound so as
to straddle a plurality of the magnetic pole teeth and is disposed
in the slots; and a rotor including a rotary shaft, a magnetic yoke
provided on an outer peripheral side of the rotary shaft, and a
plurality of permanent magnets disposed at certain intervals on an
outer peripheral surface of the magnetic yoke, wherein the coils
include armature coils for driving the rotating electric machine
and a non-armature coil for magnetizing or demagnetizing the
permanent magnets of the rotor.
2. The rotating electric machine according to claim 1, wherein the
armature coils include: a first armature coil that is disposed on
an opening side and a core back side of the slots so that the
number of magnetic pole teeth which the first armature coil
straddles is a minimum natural number larger than (the number of
slots/the number of magnetic poles); and a second armature coil
that is disposed on opening sides of the slots or core back sides
of the slots so that the number of magnetic pole teeth which the
second armature coil straddles is a largest natural number smaller
than (the number of slots/the number of magnetic poles); and the
stator is divided into a plurality of blocks, and arrangement of
the first armature coil and the second armature coil is complete
within each of the blocks.
3. The rotating electric machine according to claim 2, wherein the
non-armature coil is disposed in a slot sandwiched between the
slots in which the second armature coil is disposed.
4. The rotating electric machine according to claim 1, wherein the
number of magnetic pole teeth which the non-armature coil straddles
is a minimum natural number larger than (the number of slots/the
number of magnetic poles).
5. The rotating electric machine according to claim 1, wherein a
combination of the number of slots and the number of magnetic poles
is determined so that a greatest common divisor of the number of
slots and the number of magnetic poles is larger than 1 and the
number of slots per pole and per phase is indivisible.
6. The rotating electric machine according to claim 1, wherein the
non-armature coil is used to detect an attachment error and
eccentricity of the permanent magnets.
7. An elevator hoisting machine comprising: a rotating electric
machine that is used as a motor for the hoisting machine; a first
power source for armature coils; and a second power source for a
non-armature coil, wherein the rotating electric machine comprises:
a stator including an armature core including a back yoke having an
annular shape, a plurality of magnetic pole teeth extending
radially inward from the back yoke, and slots surrounded by the
back yoke and the magnetic pole teeth, and a plurality of coils
each of which is wound so as to straddle a plurality of the
magnetic pole teeth and is disposed in the slots; and a rotor
including a rotary shaft, a magnetic yoke provided on an outer
peripheral side of the rotary shaft, and a plurality of permanent
magnets disposed at certain intervals on an outer peripheral
surface of the magnetic yoke, wherein the coils include armature
coils for driving the rotating electric machine and a non-armature
coil for magnetizing or demagnetizing the permanent magnets of the
rotor.
8. A method for magnetizing or demagnetizing the permanent magnets
of a rotating electric machine, comprising the steps of: passing a
magnetizing or demagnetizing electric current through a
non-armature coil; and rotating a rotor by a predetermined angle,
the step of passing the magnetizing or demagnetizing electric
current and the step of rotating the rotor being repeated, wherein
the rotating electric machine comprises: a stator including an
armature core including a back yoke having an annular shape, a
plurality of magnetic pole teeth extending radially inward from the
back yoke, and slots surrounded by the back yoke and the magnetic
pole teeth, and a plurality of coils each of which is wound so as
to straddle a plurality of the magnetic pole teeth and is disposed
in the slots; and a rotor including a rotary shaft, a magnetic yoke
provided on an outer peripheral side of the rotary shaft, and a
plurality of permanent magnets disposed at certain intervals on an
outer peripheral surface of the magnetic yoke, wherein the coils
include armature coils for driving the rotating electric machine
and a non-armature coil for magnetizing or demagnetizing the
permanent magnets of the rotor.
9. The rotating electric machine according to claim 2, wherein the
number of magnetic pole teeth which the non-armature coil straddles
is a minimum natural number larger than (the number of slots/the
number of magnetic poles).
10. The rotating electric machine according to claim 2, wherein a
combination of the number of slots and the number of magnetic poles
is determined so that a greatest common divisor of the number of
slots and the number of magnetic poles is larger than 1 and the
number of slots per pole and per phase is indivisible.
11. The rotating electric machine according to claim 2, wherein the
non-armature coil is used to detect an attachment error and
eccentricity of the permanent magnets.
12. The rotating electric machine according to claim 3, wherein the
number of magnetic pole teeth which the non-armature coil straddles
is a minimum natural number larger than (the number of slots/the
number of magnetic poles).
13. The rotating electric machine according to claim 3, wherein a
combination of the number of slots and the number of magnetic poles
is determined so that a greatest common divisor of the number of
slots and the number of magnetic poles is larger than 1 and the
number of slots per pole and per phase is indivisible.
14. The rotating electric machine according to claim 3, wherein the
non-armature coil is used to detect an attachment error and
eccentricity of the permanent magnets.
15. The elevator hoisting machine according to claim 7, wherein the
armature coils include: a first armature coil that is disposed on
an opening side and a core back side of the slots so that the
number of magnetic pole teeth which the first armature coil
straddles is a minimum natural number larger than (the number of
slots/the number of magnetic poles); and a second armature coil
that is disposed on opening sides of the slots or core back sides
of the slots so that the number of magnetic pole teeth which the
second armature coil straddles is a largest natural number smaller
than (the number of slots/the number of magnetic poles); and the
stator is divided into a plurality of blocks, and arrangement of
the first armature coil and the second armature coil is complete
within each of the blocks.
16. The elevator hoisting machine according to claim 7, wherein the
non-armature coil is disposed in a slot sandwiched between the
slots in which the second armature coil is disposed.
17. The elevator hoisting machine according to claim 7, wherein the
non-armature coil is used to detect an attachment error and
eccentricity of the permanent magnets.
18. The method for magnetizing or demagnetizing the permanent
magnets of the rotating electric machine according to claim 8,
wherein the armature coils include: a first armature coil that is
disposed on an opening side and a core back side of the slots so
that the number of magnetic pole teeth which the first armature
coil straddles is a minimum natural number larger than (the number
of slots/the number of magnetic poles); and a second armature coil
that is disposed on opening sides of the slots or core back sides
of the slots so that the number of magnetic pole teeth which the
second armature coil straddles is a largest natural number smaller
than (the number of slots/the number of magnetic poles); and the
stator is divided into a plurality of blocks, and arrangement of
the first armature coil and the second armature coil is complete
within each of the blocks.
19. The method for magnetizing or demagnetizing the permanent
magnets of the rotating electric machine according to claim 8,
wherein the non-armature coil is disposed in a slot sandwiched
between the slots in which the second armature coil is
disposed.
20. The method for magnetizing or demagnetizing the permanent
magnets of the rotating electric machine according to claim 8,
wherein the non-armature coil is used to detect an attachment error
and eccentricity of the permanent magnets.
Description
TECHNICAL FIELD
[0001] The present invention relates to a rotating electric machine
including an armature that is a stator and a rotor that rotates
relative to the armature and has a permanent magnet type field
magnet, an elevator hoisting machine, and a method for magnetizing
and demagnetizing permanent magnets of the rotating electric
machine.
BACKGROUND ART
[0002] An elevator is continuously used for a long term of 20 years
or more. If a failure such as a coil insulation failure or breakage
of a magnet occurs in a rotating electric machine during use of the
elevator, it is necessary to disassemble and repair the rotating
electric machine.
[0003] An elevator hoisting machine is disclosed which includes a
stator core that is vertically divided into two portions on a shaft
center and a stator housing that also serves as a bearing stand,
holds the stator core, and is vertically divided into an upper
stator housing and a lower stator housing on the shaft center so
that a stator maintenance space is reduced and so that dividing and
reassembling operation becomes easy (see, for example, Patent
Document 1). Furthermore, a method for manufacturing a motor in
which a permanent magnet embedded in a rotor is magnetized by using
an electric current passed through a stator coil (see, for example,
Patent Document 2).
CITATION LIST
Patent Document
[0004] Patent Document 1: Japanese Patent No. 4862292 (Paragraphs
[0009] and [0011] and FIGS. 3 and 4) [0005] Patent Document 2:
Japanese Laid-Open Patent Publication No. 2002-300762 (Paragraphs
[0018] and [0039] and FIG. 1)
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0006] However, according to the invention disclosed in Patent
Document 1, it is necessary to provide a guide device to a stator
and a rotor in order to prevent the stator and the rotor from
making contact with each other due to the attraction force of a
permanent magnet in the dividing operation. Furthermore, it is
difficult to divide and reassemble the elevator hoisting machine
due to the attraction force of the permanent magnet. One solution
to this problem is the invention disclosed in Patent Document 2.
However, according to the invention disclosed in Patent Document 2,
an electric current of approximately several to several tens of kA
is needed to magnetize the permanent magnet. This may possibly
apply strong force to the coil in the magnetizing step and break
the coil itself due to contact of an insulation coating with a
core, thereby leading to a risk of markedly shortening the lifetime
of the product.
[0007] The present invention has been made to solve the above
problem, and an object of the present invention is to provide a
rotating electric machine that can be disassembled and assembled
with good workability and has good operating characteristics, an
elevator hoisting machine, and a method for magnetizing and
demagnetizing a permanent magnet of a rotating electric
machine.
Solution to the Problems
[0008] A rotating electric machine according to the present
invention includes: a stator including an armature core including a
back yoke having an annular shape, plurality of magnetic pole teeth
extending radially inward from the back yoke, and slots surrounded
by the back yoke and the magnetic pole teeth, and a plurality of
coils each of which is wound so as to straddle a plurality of the
magnetic pole teeth and is disposed in the slots; and a rotor
including a rotary shaft, a magnetic yoke provided on an outer
peripheral side of the rotary shaft, and a plurality of permanent
magnets disposed at certain intervals on an outer peripheral
surface of the magnetic yoke, wherein the coils include armature
coils for driving the rotating electric machine and a non-armature
coil for magnetizing or demagnetizing the permanent magnets of the
rotor.
[0009] An elevator hoisting machine according to the present
invention includes: the rotating electric machine that is used as a
motor for hoisting machine; a first power source for the armature
coils; and a second power source for the non-armature coil.
[0010] A method for magnetizing or demagnetizing permanent magnets
of the rotating electric machine includes the steps of: passing a
magnetizing or demagnetizing electric current through the
non-armature coil; and rotating the rotor by a predetermined angle,
the step of passing the magnetizing or demagnetizing electric
current and the step of rotating the rotor being repeated.
Effect of the Invention
[0011] In the rotating electric machine according to the present
invention, since the group of coils includes armature coils for
driving the rotating electric machine and a non-armature coil for
magnetizing or demagnetizing the permanent magnets of the rotor, it
is possible to markedly lower the attraction force of the permanent
magnets by lowering the magnetic force of the permanent magnets
before disassembling or assembling. It is therefore possible to
perform disassembling and assembling operation with good
workability and to achieve good operating characteristics.
[0012] In the elevator hoisting machine according to the present
invention, since the aforementioned rotating electric machine is
used, it is possible to magnetize or demagnetize the permanent
magnets of the rotating electric machine by using the non-armature
coil. It is therefore possible to improve work efficiency during
installation and inspection.
[0013] In the method for magnetizing or demagnetizing the permanent
magnets of the rotating electric machine according to the present
invention, since the step of passing the magnetizing or
demagnetizing electric current through the non-armature coil and
the step of rotating the rotor by the predetermined angle are
repeated, it is possible to improve work efficiency during
installation and inspection of the rotating electric machine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a configuration diagram according to a rotating
electric machine of Embodiment 1 of the present invention.
[0015] FIG. 2 is a configuration diagram of a coil according to the
rotating electric machine of Embodiment 1 of the present
invention.
[0016] FIG. 3 is a coil arrangement expansion diagram according to
the rotating electric machine of Embodiment 1 of the present
invention.
[0017] FIG. 4 is a comparison diagram compared with the coil
arrangement expansion diagram according to the rotating electric
machine of Embodiment 1 of the present invention.
[0018] FIG. 5 is a diagram for explaining division of a stator
according to the rotating electric machine of Embodiment 1 of the
present invention.
[0019] FIG. 6 is a diagram for explaining a magnetic path created
by non-armature coils according to the rotating electric machine of
Embodiment 1 of the present invention.
[0020] FIG. 7 is a configuration diagram according to an elevator
hoisting machine of Embodiment 4 of the present invention.
DESCRIPTION OF EMBODIMENTS
Embodiment 1
[0021] Embodiment 1 relates to a rotating electric machine that
includes: a stator divided into a plurality of blocks including an
armature core having slots formed between magnetic pole teeth, and
a plurality of coils each of which is wound so as to straddle a
plurality of the magnetic pole teeth; and a rotor including a
plurality of permanent magnets that are disposed at certain
intervals on an outer peripheral surface of a magnetic yoke
provided on an outer peripheral side of a rotary shaft. The coils
include an armature coil for driving the rotating electric machine
and a non-armature coil for magnetizing or demagnetizing the
permanent magnets of the rotor.
[0022] The structure and operation of the rotating electric machine
according to Embodiment 1 of the present invention will be
described below with reference to FIG. 1, which is a configuration
diagram of the rotating electric machine, FIG. 2, which is a
configuration diagram of coils, FIG. 3, which is a coil arrangement
expansion diagram, FIG. 4, which is a comparison diagram compared
with the coil arrangement expansion diagram, FIG. 5, which is a
diagram for explaining division of a stator, and FIG. 6, which is a
diagram for explaining a magnetic path created by non-armature
coils.
[0023] First, the overall configuration of a rotating electric
machine 10 according to Embodiment 1 of the present invention will
be described with reference to FIGS. 1 and 2. FIG. 1 illustrates a
cross section that is orthogonal to the axial direction of the
rotating electric machine 10.
[0024] The rotating electric machine 10 includes a stator 20 that
has a cylindrical shape and a rotor 30 that is disposed within the
stator 20 and rotates therein. The stator 20 has a function as an
armature, and the rotor 30 has a function as a field magnet.
[0025] Although both the armature and the field magnet are
components that generate a magnetic field for obtaining torque, a
component that generates a constant magnetic field is called a
field magnet and a component that generates a magnetic field that
is variable depending on the magnitude or the frequency of an
inputted electric current, or the like is called an armature.
[0026] The rotor 30 is made of a magnetic steel sheet or a magnetic
material such as cast iron and includes a rotary shaft 40, a
magnetic yoke 31 that forms a magnetic path, a rotor support member
32 interposed between the rotary shaft 40 and the magnetic yoke 31,
and a plurality of permanent magnets 33 provided on the outer
peripheral surface of the magnetic yoke 31.
[0027] The permanent magnets 33 are disposed at certain intervals
in the circumferential direction of the magnetic yoke 31 and form a
plurality of magnetic poles. In this example, 40 permanent magnets
33 are provided, and the number of magnetic poles P is 40
accordingly. The permanent magnets 33 are desirably disposed at
regular intervals in the circumferential direction of the magnetic
yoke 31.
[0028] The stator 20 is made of, for example, a magnetic steel
sheet and includes an armature core 21 that forms a magnetic path,
an insulating member (not illustrated), and a group of coils
23.
[0029] The armature core 21 includes a back yoke 211 having an
annular shape, a plurality of magnetic pole teeth 212 that extend
radially inward from the back yoke 211, and slots 213 that are
regions surrounded by the back yoke 211 and the magnetic pole teeth
212. The number of the magnetic pole teeth 212 is the same as the
number of the slots 213. In this example, each of the number of
magnetic pole teeth and the number of slots Q is 105.
[0030] The insulating member is provided so as to surround inner
peripheries of the slots in order to prevent electric short circuit
between the armature core 21 and the group of coils 23. Since the
group of coils 23 has a plurality of phases as described later,
phase-to-phase insulation paper that insulates the phases from one
another, a wedge that prevents the coils from coming out the slots,
varnish in which the group of coils is immersed, and the like are
also included in this insulating member (each of these members is
not illustrated).
[0031] The group of coils 23 is functionally divided into two kinds
of coils, i.e., armature coils 231 that generate a magnetic field
for obtaining torque of the rotating electric machine 10 and
non-armature coils 232 other than the armature coils 231.
[0032] The armature coils 231 are divided into a plurality of
phases in order to smoothly drive the rotating electric machine 10.
In this example, the armature coils 231 are divided into three
phases: a U phase, a V phase, and a W phase.
[0033] A plurality of coils 230 constitute each phase of armature
coils 231, and the number of coils in each phase is the same as
that in another phase. Each of the coils 230 has two coil sides
241, two coil ends 242 that connect the coil sides 241 at the upper
and lower ends of the armature core 21, and coil terminals 243 to
be joined to other coils 230, as illustrated in FIG. 2. The two
coil sides 241 are provided so as to straddle a plurality of the
magnetic pole teeth 212 and are disposed in different slots 213,
respectively.
[0034] Each of the coils 230 is composed of, for example, a wire in
which an insulating layer is provided on the surface of copper,
aluminum, or the like and which has a wire diameter of
approximately .phi.0.2 to .phi.1.0 (a size that fits in the slots
213) and is wound several to several tens of turns. Each turn may
be constituted by a plurality of thin wires so that the coils 230
are more easily inserted into the slots 213.
[0035] The armature coils 231 are configured such that the
respective coils 230 are connected in series or in parallel, and
one terminal of each coil is connected to a control circuit or to
both the control circuit and a coil terminal of another phase, and
the other terminal of each coil is connected to a coil terminal of
another phase or to both the control circuit and a coil terminal of
another phase.
[0036] In the case where one terminal is connected to the control
circuit and the other terminal is connected to a coil terminal of
another phase, such a circuit is called a star circuit. Meanwhile,
in the case where one terminal is connected to both the control
circuit and a coil terminal of another phase and the other terminal
is connected to both the control circuit and a coil terminal of
another phase, such a circuit is called a delta circuit.
[0037] Coils 230 used as the non-armature coils 232 also have the
same configuration as that described above.
[0038] One or more non-armature coils 232 are provided, and the
non-armature coils 232 have no phase. In the case where the
non-armature coils 232 are a plurality of coils 230, it is
desirable that each of the coils be wound in a reverse direction to
an adjacent coil and that the coils be connected in series.
[0039] Next, the positional relationship between the armature coils
231 and the non-armature coils 232 will be described with reference
to the expansion diagram.
[0040] FIG. 3 is an expansion diagram illustrating part of the
rotating electric machine 10 according to Embodiment 1 of the
present invention. FIG. 4 illustrates an example in which no
non-armature coil 232 is provided and the armature coils 231 are
disposed in all of the slots in an optimum manner without changing
the configuration of the armature core 21. FIG. 4 is used as a
comparison diagram for describing arrangement of the group of
coils.
[0041] In the example of Embodiment 1, the number of magnetic poles
P is 40, and the number of slots Q is 105. FIGS. 3 and 4 illustrate
part (referred to as a block 1) of 72.degree. obtained by dividing
the rotating electric machine 10 by 5, which is the greatest common
divisor of P and Q. This corresponds to an angle (X=72.degree.) for
one block in FIG. 1.
[0042] Numerals on the outer sides of the slots in the schematic
diagrams of FIGS. 3 and 4 are slot numbers assuming that the
leftmost slot in FIGS. 3 and 4 has a slot number 1. U, V, and W in
FIGS. 3 and 4 are characters representative of phases of the coils.
The symbols added to the phases represent directions in which
electric current flows through the coils. Specifically, + indicates
that an electric current flows upward on the paper, and - indicates
that an electric current flows downward on the paper. The lines
that connect the slots so as to straddle the magnetic pole teeth in
FIGS. 3 and 4 indicate a way in which coil ends are connected and a
direction of flow of an electric current.
[0043] It is desirable that the coils of the three phases be
arranged in a periodical pattern in the circumferential direction
in order to achieve well-balanced driving of the rotating electric
machine 10. In the example of Embodiment 1, the coils are arranged
periodically in a cycle of angles (72.degree. in this example)
obtained by dividing the rotating electric machine 10 by 5, which
is the greatest common divisor of P and Q.
[0044] Furthermore, it is desirable that a synthetic vector of a
magnetomotive force or an inductive voltage created by the armature
coils of each phase be the same as that created by the armature
coils of another phase so that a phase difference is equally
divided into an electric angle of 120.degree..
[0045] In FIG. 3, the armature coils 231 include two kinds of coils
230 (a first armature coil and a second armature coil).
[0046] The first armature coil 231A has coil sides on an upper side
(opening side) and a lower side (core back side) of slots. The
number of the magnetic pole teeth 212 which the first armature coil
231A straddles is a minimum natural number exceeding (the number of
slots/the number of magnetic poles) (3 because 105/40=2.625 in the
case of FIG. 3).
[0047] The second armature coil 231B has coil sides on upper sides
or lower sides of slots. The number of the magnetic pole teeth 212
which the second armature coil 231B straddles is a maximum natural
number that does not exceed (the number of slots/the number of
magnetic poles) (2 in the case of FIG. 3).
[0048] Procedures for disposing the second armature coil 231B will
be described below with reference to FIG. 4 in which the armature
coils 231 are disposed in all of the slots in an optimum
manner.
[Procedure 1] Attention is paid to the leftmost and rightmost coils
in one block of FIG. 4. Such coils are the slot number 1 and the
slot number 21 in this example. [Procedure 2] Attention is paid to
coils: the coils are disposed in slots within the range of a
natural number (2) that is below (the number of slots/the number of
magnetic poles) from the slot numbers 1 and 21; they are located in
the same positions (upper side or lower side) in the slots; and
they have the same phases, and in which an electric current flows
in a reverse direction. Such coils are V+ of the slot number 3 in
the case of V- of the slot number 1 and V+ of the slot number 19 in
the case of V- of the slot number 21. [Procedure 3] Since
electromagnetic action does not change even if coil sides found in
the procedure 2 are connected, the coil sides are reconnected.
Second armature coils are created by using the slot numbers 1 and 3
and using the slot numbers 19 and 21. [Procedure 4] Coils in the
other phases that are in the same relationship as the second
armature coils created in the procedure 3 are also found and are
configured in the same way. In the example of Embodiment 1, the
number of the slots is 21, and the number of the phases is 3.
Accordingly, this relationship appears every 7 teeth. Taking note
of this, second armature coils are further created by using the
slot numbers 8 and 10, the slot numbers 15 and 17, the slot numbers
5 and 7, and the slot numbers 12 and 14.
[0049] The armature coils 231 of each phase include the same number
of first armature coils and the same number of second armature
coils as the armature coils 231 of another phase. In FIG. 3, among
six coils per phase, four coils are first armature coils, and two
coils are second armature coils determined in the procedures 1
through 4 described above. This makes it possible to achieve
uniform coil resistance in the phases, thereby reducing variations
in electric current passing through the coils during driving.
[0050] In the above description, the case where the number of the
slots is 105 and the number of the poles is 40 has been described.
However, other combinations are also possible. For example, the
aforementioned combination of first armature coils and second
armature coils is found in the case where the value of (the number
of slots/the number of magnetic poles) is larger than the value
obtained by subtracting 1 from the number of the phases and is
smaller than the number of the phases, for example, in the case
with where 108 slots and 42 poles.
[0051] Furthermore, in Embodiment 1, attention is paid to coils
that are not connected in one block (obtained by dividing the
stator by the greatest common divisor of the number of slots Q and
the number of magnetic poles P) among the coils other than the
second armature coils in FIG. 4. On the left side of FIG. 4, such a
coil is W- on the lower side of the slot number 2 sandwiched
between V- of the slot number 1 and V+ of the slot number 3 that
constitute a second armature coil.
[0052] On the right side of FIG. 4, such a slot is U+ on the upper
side of the slot number 20 sandwiched between V+ of the slot number
19 and V- of the slot number 21.
[0053] Being not connected in one block means that removing such
coils from the group of coils completes the coil arrangement per
block. Accordingly, a divided structure of the stator is achieved
even in the case of distributed winding.
[0054] However, in order to obtain a rotating electric machine
having a divided structure by removing such coils from the group of
coils, it is necessary to remove coils at similar positions in one
block from the group of coils so that balance among the coils of
the three phases is achieved. The positions of the removed coils
are positions obtained by equally dividing 21 slots as in the
procedure 4 for disposing the second armature coils. That is, it is
only necessary to remove a coil every 7 teeth.
[0055] Specifically, in FIG. 4, such coils are V+ on the lower side
of the slot number 9, W+ on the lower side of the slot number 16,
W- on the upper side of the slot number 13, and V- on the upper
side of the slot number 6.
[0056] In this way, the group of coils fits within one block
without breaking the balance among the three phases. That is, the
coil arrangement is complete within the block, and coils are not
connected between blocks.
[0057] The divided structure of the rotating electric machine 10 in
the case where the group of coils fits within one block will be
described below with reference to FIG. 5.
[0058] FIG. 5 is a diagram for explaining division in the case
where the stator 20 of the rotating electric machine 10 of FIG. 1
is divided into 5 blocks, wherein only one block is enlarged away
from a center of assembling. In FIG. 5, components, such as a
housing, attached to the stator 20 are omitted.
[0059] The number of slots in each block 201 of the rotating
electric machine 10 of FIG. 5 is 21, which is the same as the
number of slots in the block of the rotating electric machine 10
illustrated in FIG. 3. A division surface 202 corresponds to a
substantially central position of a tooth adjacent to a slot in
which the second armature coil described above is disposed. That
is, it is desirable that the stator 20 of the rotating electric
machine 10 be divided at positions where the first armature coil
231A and the second armature coil 231B do not straddle the
teeth.
[0060] In Embodiment 1, the number of divisions is 5, which is the
greatest common divisor of 105, which is the number of slots, and
40, which is the number of magnetic poles. This is because, in the
rotating electric machine 10 according to Embodiment 1, positional
relationships of slots, coils, and magnets are repeated in a cycle
of the numbers obtained by dividing the number of slots and the
number of magnetic poles by the greatest common divisor, i.e., in a
cycle of 21 slots and 8 magnetic poles. However, the number of
divisions may be smaller than the greatest common divisor.
[0061] In this case, it is desirable that the number of slots in
each divided block be an integral multiple of the number (21 in
this example) obtained by dividing the total number of slots by the
aforementioned greatest common divisor. Also in the case with the
aforementioned other combination of the number of slots and the
number of magnetic poles, the number of divisions may be the
greatest common divisor of the number of slots and the number of
magnetic poles or may be smaller than the greatest common
divisor.
[0062] By thus dividing the rotating electric machine, a
distributed-winding rotating electric machine that can be
conventionally configured only as an integral circle can be divided
into a plurality of blocks in the circumferential direction. This
makes it possible to easily assemble and disassemble even a
large-size rotating electric machine because each block has a small
size and light weight.
[0063] Next, a result of calculation of a winding factor in this
coil arrangement will be described.
[0064] The winding factor is represented by the product of a
distributed winding factor (a value indicating that a plurality of
coils belonging to a certain phase are not fixed at certain
positions relative to a center of a magnetic pole of a field magnet
and are distributed; the maximum is 1) and a short pitch winding
factor (a ratio of one coil pitch and a magnetic pole pitch). The
winding factor generally has odd-numbered orders (first order,
fifth order, seventh order, . . . ) excluding the number of phases,
and the first order corresponds to a fundamental wave for driving
the rotary machine, and the other orders correspond to harmonics
that generate torque ripples.
[0065] That is, it can be said that a rotating electric machine, in
which the first order component of the distributed winding factor
is closer to 1 and the other harmonics components are closer to 0,
more easily produces torque with smaller torque ripples.
[0066] The winding factor of the rotating electric machine
according to Embodiment 1 of the present invention is 0.943 (first
order), 0.155 (fifth order), and 0 (seventh order) in FIG. 3.
[0067] The winding factor of the rotating electric machine
illustrated in FIG. 4 as an optimum comparative example in which
all of the coils are armature coils is 0.932 (first order), 0.085
(fifth order), and 0 (seventh order). That is, the winding factor
that is almost equivalent to that in FIG. 4 is also obtained in the
rotating electric machine according to Embodiment 1 illustrated in
FIG. 3 (in the case where some of the coils are replaced with
non-armature coils). It can therefore be said that the rotating
electric machine 10 has good operating characteristics.
[0068] Next, the non-armature coils 232 will be described.
[0069] The non-armature coils 232 are disposed at slot positions
sandwiched between slots that constitute second armature coils.
[0070] In FIG. 3, such slot positions are the upper side of the
slot number 6, the lower side of the slot number 9, the upper side
of the slot number 13, and the lower side of the slot number 16.
That is, in FIG. 3, the non-armature coils are coils indicated by
hatching and thick arrows.
[0071] In FIG. 3, there are other slots located between slots that
constitute second armature coils, but it is unnecessary to dispose
coils in these slots. Such slots are the lower side of the slot
number 2 and the upper side of the slot number 20.
[0072] It is desirable that the coil pitch of the non-armature
coils be the same as that of first armature coils. In FIG. 3, the
coil pitch between the slot number 6 and the slot number 9 and the
coil pitch between the slot number 13 and the slot number 16 are 3,
which is the same as that of first armature coils.
[0073] As the non-armature coils 232, one or two coils 230 are
provided per block. The non-armature coils 232 may be provided in
each of the blocks or may be provided in one or more blocks.
[0074] The non-armature coils 232 are not coils for driving the
rotating electric machine, but coils used for improvement of ease
of maintenance such as disassembly, assembly, and inspection of the
rotating electric machine.
[0075] In Embodiment 1, a method for using the non-armature coils
232 as magnetizing or demagnetizing coils will be described.
[0076] It is desirable that the coils 230 used as the non-armature
coils 232 have a thicker insulating layer and be wound a smaller
number of turns than the coils used as the armature coils 231.
[0077] For example, an insulating tape having a thickness of
approximately 25 .mu.m to 125 .mu.m may be wound as the insulating
layer. It is desirable that the number of turns be one to several
turns per coil. Furthermore, it is desirable that the coils 230
used as the non-armature coils 232 be connected in series.
[0078] Furthermore, it is desirable that the non-armature coils 232
be connected to a power source different from a power source for
driving the rotating electric machine as described in Embodiment 4
(see FIG. 7 of Embodiment 4).
[0079] Next, a method for magnetizing the permanent magnets 33 by
using the non-armature coils 232 will be described with reference
to FIG. 6.
[0080] FIG. 6 is a diagram illustrating lines of magnetic flux,
density of magnetic flux, and direction of magnetic flux obtained
when an electric current (several tens of kA) needed for
magnetizing is applied to the non-armature coils 232. In FIG. 6, no
armature coil is illustrated.
[0081] In FIG. 6, in the case where the permanent magnets 33 are
rare-earth magnets, a magnetic field of several tens of kAT (AT:
electric current.times.the number of turns; called magnetomotive
force or ampere-turn) is applied to the non-armature coils 232. A
rare-earth magnet is generally magnetized 100% when the density of
magnetic flux is 2 or more teslas. The arrows in FIG. 6 indicate
only portions where the density of magnetic flux is 2 or more
teslas, and the permanent magnets are magnetized in the directions
indicated by the arrows. The number of turns of the non-armature
coils 232 is approximately one to several turns, and a magnetizing
electric current is generally approximately several to several tens
of kA although the magnetizing electric current depends on a
magnetic circuit.
[0082] Referring to FIG. 6, the third and sixth permanent magnets
33 from the right of FIG. 6 are magnetized to an S pole and an N
pole, respectively, by the non-armature coils 232. Since the
magnetic poles in a rotor are arranged alternately as S poles and N
poles starting from the first magnet, the permanent magnets 33 in
FIG. 6 are magnetized in a correct direction of magnetic flux.
[0083] In the case of demagnetizing the permanent magnets 33, an AC
current that gradually attenuates is applied to the non-armature
coils 232. For example, it is possible to employ a method of
charging a capacitor with an electric charge of several thousands
of .mu.F in advance and passing an electric current through the
non-armature coils 232 by connecting the non-armature coils 232 to
the capacitor by using a switch. In this case, the applied electric
current gradually attenuates due to the resistance and inductance
of the non-armature coils 232, and therefore the permanent magnets
33 can be demagnetized.
[0084] Since a large electromagnetic force acts on the non-armature
coils 232 during magnetizing, it is desirable to make the
insulating layers of the coils thick as described above and fix the
coils in the slots. A method for fixing the coils is, for example,
a method using varnish, an adhesive, a spacer, or the like.
[0085] This magnetizing or demagnetizing operation is performed
several times while the position of the rotor 30 is rotated,
whereby magnetizing or demagnetizing of all of the permanent
magnets 33 is completed. For example, in the case where the
non-armature coils 232 are 10 coils in total (2 coils per
block.times.5 blocks), all of the permanent magnets 33 can be
magnetized or demagnetized by repeating the operation four
times.
[0086] In the repeated magnetizing or demagnetizing operation, the
position of the rotor 30 may be determined by using information
from a rotation sensor (not illustrated) such as a resolver or an
encoder attached as standard equipment to the rotating electric
machine or may be mechanically determined by using a jig or the
like.
[0087] As described above, the operation of magnetizing or
demagnetizing the permanent magnets 33 of the rotor 30 is completed
by repeating, necessary times, a step of passing a magnetizing or
demagnetizing electric current through the non-armature coils 232
and a step of rotating the rotor 30 by a predetermined angle.
[0088] The predetermined angle and the necessary times are
determined on the basis of the arrangement of the permanent magnets
33 and the arrangement of the non-armature coils 232. In the
example of Embodiment 1, the predetermined angle is 90.degree., and
the necessary times is four times.
[0089] The rotating electric machine 10 can have any size. For
example, in the case where the rotating electric machine 10 is used
in an elevator hoisting machine, the rotating electric machine 10
may have a size of several hundreds of millimeters to several
meters in diameter. In the case where such a large-size rotating
electric machine is installed, it can be assumed that when a need
for repair, inspection, replacement, assembly, or the like of the
large-size rotating electric machine arises, a sufficient space for
installation cannot be ensured and the operation cannot easily be
performed.
[0090] In the case where the rotating electric machine 10 according
to Embodiment 1 is used in an elevator hoisting machine, it is
possible to easily perform repair, inspection, replacement,
assembly, or the like even in a narrow space because the stator 20
can be divided by the greatest common divisor of the number of
slots and the number of magnetic poles and because the permanent
magnets 33 of the rotor 30 can be magnetized or demagnetized in a
state where the rotating electric machine 10 is assembled.
[0091] In the case where the housing (not illustrated) that holds
the stator also has a divided structure as with the stator, ease of
maintenance is further improved.
[0092] As described above, the rotating electric machine according
to Embodiment 1 includes: a stator including an armature core
having slots formed between magnetic pole teeth, and a plurality of
coils each of which is wound so as to straddle a plurality of the
magnetic pole teeth so that coil sides thereof are disposed in the
slots; and a rotor including a plurality of permanent magnets that
are disposed at certain intervals on an outer peripheral surface of
a magnetic yoke provided on an outer peripheral side of a rotary
shaft. The coils include an armature coil for driving the rotating
electric machine and a non-armature coil for magnetizing or
demagnetizing the permanent magnets of the rotor. It is therefore
possible to provide a rotating electric machine that can be
disassembled and assembled with good workability because a stator
can be easily divided and that has good operating
characteristics.
Embodiment 2
[0093] A rotating electric machine according to Embodiment 2 has a
combination of the number of slots and the number of magnetic poles
that is different from that of the rotating electric machine
according to Embodiment 1 (the number of slots is 105 and the
number of magnetic poles 40).
[0094] The conditions of the rotating electric machine according to
Embodiment 2 will be described below.
[0095] The following conditions need be satisfied by the
combination of the number of slots and the number of magnetic poles
with which the rotating electric machine according to Embodiment 1
to which the present invention is applicable, i.e., a rotating
electric machine including distributed winding coils can be divided
in the circumferential direction and a structure in which a
non-armature coil can be provided can be configured.
[0096] [Condition 1] The greatest common divisor of the number of
slots and the number of magnetic poles is larger than 1 (coils are
arranged periodically in a cycle of angles that can divide a
mechanical angle 360.degree.).
[0097] [Condition 2] The number of slots per pole and per phase is
indivisible (even lap winding and distributed winding coils have
two kinds of coil pitches).
[0098] Combinations of the number of slots and the number of
magnetic poles that satisfy the conditions 1 and 2 are, for
example, a combination of 180 slots and 70 poles (5 divisions) and
a combination of 135 slots and 50 poles (5 divisions). Any of these
combinations can be employed.
[0099] Furthermore, combinations such as a combination of 108 slots
and 42 poles (3 divisions) and a combination of 81 slots and 30
poles (3 divisions) also satisfy the conditions 1 and 2.
[0100] As described above, the rotating electric machine according
to Embodiment 2 has a combination of the number of slots and the
number of magnetic poles that satisfies the conditions 1 and 2, and
therefore it is possible to provide a rotating electric machine
that can be disassembled and assembled with good workability
because a stator can be easily divided and that has good operating
characteristics as in Embodiment 1.
Embodiment 3
[0101] A rotating electric machine according to Embodiment 3 is a
rotating electric machine in which the non-armature coils according
to Embodiment 1 are used for a purpose different from magnetizing
or demagnetizing of permanent magnets.
[0102] The rotating electric machine according to Embodiment 3 will
be described below. In the following description, the drawings of
Embodiment 1 are referred to as appropriate, and the reference
signs of the respective constituent elements of Embodiment 1 are
used.
[0103] The non-armature coils 232 can be used not only for
magnetizing or demagnetizing, but also for improvement of ease of
maintenance of the rotating electric machine 10. For example, a
non-armature coil 232 that is wound several to several tens of
turns is disposed at the same position in each block. The phase and
the magnitude of an inductive voltage generated in this
non-armature coil 232 during rotation of the rotor 30 are
measured.
[0104] That is, an attachment error, eccentricity, and the like of
the permanent magnets 33 can be detected by using the non-armature
coil as a search coil.
[0105] As the specifications of the search coil, a thin wire may be
wound a large number of turns unlike the magnetizing or
demagnetizing coils described in Embodiment 1. By winding the wire
a large number of turns, it is possible to improve the sensitivity
of detection. In order to improve the accuracy as the search coil,
it is desirable to use an adhesive or a spacer to fix the search
coil to a slot as in the case of a magnetizing coil.
[0106] Embodiment 3 may be combined with Embodiment 1. For example,
non-armature coils may be disposed as magnetizing or demagnetizing
coils in first and second blocks, and non-armature coils may be
disposed as search coils in third to fifth blocks.
[0107] Furthermore, a non-armature coil disposed as a magnetizing
or demagnetizing coil may be used as a search coil during normal
operation.
[0108] As described above, the rotating electric machine according
to Embodiment 3 is a rotating electric machine in which the
non-armature coils according to Embodiment 1 are used for a purpose
different from magnetizing or demagnetizing of permanent magnets.
It is therefore possible to provide a rotating electric machine
that can be disassembled and assembled with good workability
because a stator can be easily divided and that has good operating
characteristics as in Embodiment 1.
[0109] Furthermore, in the rotating electric machine according to
Embodiment 3, by using non-armature coil as a search coil, it is
possible to detect an attachment error, eccentricity, and the like
of the permanent magnets, thereby improving ease of
maintenance.
Embodiment 4
[0110] An elevator hoisting machine according to Embodiment 4 is a
hoisting machine in which any of the rotating electric machines
described in Embodiments 1 to 3 is used as a motor.
[0111] The configuration and operation of the elevator hoisting
machine according to Embodiment 4 will be described below with
reference to FIG. 7 which is a configuration diagram of the
elevator hoisting machine.
[0112] In FIG. 7, an elevator hoisting machine 400 includes the
rotating electric machine 10, a driving power source (first power
source) 51 that supplies power to armature coils 231 and a
non-armature coil power source (second power source) 52 that
supplies power to the non-armature coils 232. The rotating electric
machine 10, which is a motor for a hoisting machine, is any of the
rotating electric machines described in Embodiments 1 to 3.
[0113] During normal operation of the rotating electric machine 10
of the elevator hoisting machine 400, PWM-controlled three-phase AC
power is, for example, supplied from the driving power source
(first power source) 51 to the rotating electric machine 10.
[0114] During mounting, inspection, or disassembling of the
rotating electric machine 10, an electric current necessary for
magnetizing and demagnetizing of the permanent magnets 33 is
supplied from the non-armature coil power source (second power
source) 52 to the non-armature coils 232 of the rotating electric
machine 10.
[0115] Furthermore, during normal operation of the rotating
electric machine 10 of the elevator hoisting machine 400, an
attachment error, eccentricity, and the like of the permanent
magnets 33 can be detected by measuring the phase and the magnitude
of an inductive voltage generated in the non-armature coil 232
disposed as a search coil.
[0116] Measurement of an inductive voltage generated in this
non-armature coil 232 and detection of an attachment error,
eccentricity, and the like of the permanent magnets 33 can also be
performed by a device included in the non-armature coil power
source (second power source) 52. Alternatively, an attachment
error, eccentricity, and the like of the permanent magnets 33 may
be detected by connecting a device for measuring the phase and the
magnitude of an inductive voltage generated in the non-armature
coil 232 as needed.
[0117] As described above, the elevator hoisting machine according
to Embodiment 4 is a hoisting machine in which any of the rotating
electric machines described in Embodiments 1 to 3 is used. It is
therefore possible to magnetize or demagnetize the permanent
magnets of the rotating electric machine by using the non-armature
coil, thereby improving work efficiency during installation and
inspection.
[0118] Furthermore, ease of maintenance of the rotating electric
machine can be improved by using the non-armature coil as a search
coil.
[0119] It is noted that, within the scope of the present invention,
the above embodiments may be freely combined with each other, or
each of the above embodiments may be modified or simplified as
appropriate.
INDUSTRIAL APPLICABILITY
[0120] The present invention includes an armature coil for driving
a rotating electric machine and a non-armature coil for magnetizing
or demagnetizing permanent magnets of a rotor and is widely
applicable to a rotating electric machine that is required to have
improved work efficiency during installation and inspection.
* * * * *